If a matrix has 18 elements, what are the possible orders it can have? What, if it has 5 elements?

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We know that a matrix of order m × n has mn elements.
Then the possible orders are 1 × 18, 18 × 1, 2 × 9, 9 × 2, 3 × 6, 6 × 3.

If a matrix has 5 elements, then possible orders are 1 × 5 and 5 × 1.